Project Summary Childhood apraxia of speech (CAS) is a pediatric motor speech disorder that impairs the planning of movements needed for intelligible speech. CAS may limit literacy, academic and economic outcomes and participation in society. Approximately 40,000 to 160,000 children under 10 have CAS in the US, and over 60% of school-based speech-language pathologists have children with CAS on their caseload, with on average 3 children per caseload. Children with CAS often show little or slow progress in standard speech therapy, which has led to recommendations for intensive intervention and calls for systematic research to optimize outcomes. Given the limited resources in clinical settings, it is imperative to maximize impact of these limited resources for children with CAS. This proposal fits with NIDCD?s Strategic Plan in that it aims to develop and test an effective treatment for an explicitly noted understudied population (CAS). Various treatment approaches for CAS exist, with integral stimulation treatment (?watch me, listen to me, say what I say?) being the only treatment method to date with independently replicated support. Nevertheless, the current evidence base is limited both in study quality and scope. In terms of study quality, all studies to date have involved single-case experimental designs with small sample sizes and varying methodological rigor. In terms of scope, the extant studies vary considerably with respect to important treatment parameters that may critically impact outcomes. Two such important yet poorly understood parameters relate to optimal target selection and optimal treatment intensity. Another limitation of scope is that virtually all studies have relied exclusively on impairment-level outcome measures, and have not included more functional outcome measures related to activity and participation. For these reasons, speech-language pathologists lack adequate information to make clinical decisions for their clients. The proposed research is a Phase I study that tests initial efficacy and optimal parameters of a theoretically based integral stimulation treatment called ASSIST (Apraxia of Speech Systematic Integral Stimulation Treatment). In three small randomized group design studies, children (N=20 per study) receive 16 hours of individual ASSIST. The three studies systematically investigate treatment intensity (2 vs. 4 weeks) and two critical aspects of target selection: complexity (simple vs. complex target) and lexicality (words vs. nonwords). Each study also systematically examines the effect of treatment on functional outcome measures, including parent ratings of intelligibility and communicative participation, and objective intelligibility measures obtained from unfamiliar listeners. Thus, this research will gather vital information for a Phase II trial of preliminary efficacy and contribute high-quality evidence that will help speech-language pathologists make evidence-based clinical decisions. The long term goal of this research program is to develop optimally effective treatments to maximize outcomes and communicative quality of life for the many children with CAS and their families.